Dairy calves are subjected to an environment rich in pathogenic bacteria and microbial agents soon after birth. The calves are inherently susceptible to these agents because they are essentially born without natural immunity. As a result, infectious diseases are the main cause of calf morbidity and mortality during their first few weeks of life.
The death rate of calves can be decreased by the passive transfer of immunoglobulin from the mother cow to the new calf. This passive transfer can be achieved naturally by colostrum. Colostrum is the milk secreted for the first few days after birth and is characterized by high protein and antibody content. However, calves can only absorb antibodies soon after birth, and efforts to transfer immunity through colostrum are often unsuccessful.
At times, more than 30% (Donovan et al., "Factors influencing passive transfer of dairy calves," J. Dairy Sci. 69: 754-759, 1986; Norheim, et al., "An epidemiological studies of factors affecting serum IgG levels in dairy calves," Nord. Vet. 37: 121-135, 1985) of newborn calves do not develop immunity, or experience failure in passive transfer (McGuire et al., "Failure of colostral immunoglobulin transfer in calves dying from infectious disease," J. Am. Vet. Med. Assoc. 169: 713-718, 1976; McEwan et al., "Observations on the immune globulin levels of neonatal calves and their relationship to disease," J. Comp. Pathol. 80: 259-265, 1970; Gay et al., "Gamma globulin levels and neonatal mortality in market calves," Vet. Rec. 77: 148-149, 1965).
The passive immunity of new-born calves is boosted by colostrum, so the dairy industry has developed colostrum-based products that are purported to enhance the immune system. Because natural microflora protect calves from pathogens, lactic acid bacteria have been used as probiotics. Probiotics are bacteria which colonize the digestive tract and prevent colonization of pathogenic organisms.
In nature, the calf is in constant contact with the mother cow. The mother frequently licks the muzzle of the calf, and this "grooming" is a source of ruminal microorganisms. When reared on dairy farms, the calves typically are removed from the mother so that grooming is no longer possible. Calves that are taken from the mother at birth and reared in isolation lack ruminal protozoa, but these animals eventually develop a ruminal flora that contains bacteria. Ruminal fluid has never been used as a milk additive for suckling dairy calves.
An alternative to colostrum is the immunization of very young calves with conventional vaccines. However, this often fails to offer the broad protection a newborn calf needs (Selim et al., "The effect of Escherichia coli J5 and modified live Salmonella dublin vaccines in artificially reared neonatal calves," Vaccine 13; 381-390, 1995; Husband and Lascelles, "Antibody responses to neonatal immunization in calves," Res. Vet. Sci. 18: 201-207, 1975).
The sanitation and air quality of calf facilities have improved and calves are frequently isolated in "hutches" to inhibit the transmission of pathogens. However, calf health and morbidity continues to be a serious problem for the dairy cattle industry. Calves can be given low levels of antibiotics as growth promotants or larger doses as veterinary therapy, but widespread use of antibiotics in the animal industry has been criticized by the human medical field.
U.S. Pat. No. 5,785,990 to Langrehr discloses a feed fortifier and enhancer for pre-ruminant calves and a method of using the same. The inventor claims a feed fortifier containing many components. This feed fortifier results in a reduced incidence and severity of scours, a condition also studied by the present inventors as a measure of health. Generally, the patent claims that the overall health of the calves improved. However, the patent does not disclose the specific use of ruminal fluid in the feed fortifier.
U.S. Pat. No. 5,670,196 to Gregory discloses a method for microfiltration of milk or colostral whey. The invention provides a method of microfiltering milk, milk serum, colostrum, or colostral serum which provides effective bioburden reduction without substantial loss of immunoglobulins, substantially reducing the bioburden in the product while providing high immunoglobulin yields. The method makes use of charged depth filters to provide consistent bioburden control, resulting in whey products fortified with immunoglobulins.
U.S. Pat. No. 5,198,213 to Stott et al. discloses a method of disease treatment utilizing an immunologically active whey fraction. The whey is ultrafiltered through one or more different process steps to yield a filtered product having a concentration of immunologically active immunoglobulin of at least about seven percent of total solids. The filtered product is periodically tested to verify its activity to a specified microbe. The filtered product is orally administered in a therapeutically effective dose to an animal to treat a disease.
U.S. Pat. No. 4,834,974 to Stott et al. discloses an immunologically active whey fraction and recovery process. A dry, immunologically active filtered product is produced through the controlled one or two stage ultrafiltration of liquid whey containing immunologically active immunoglobulin (Ig). When fed to newborn calves, the product functions as a substitute for natural colostrum, providing both temporary passive immunity as well as initiation of the active immune system of the animal. Disease resistance and growth rate in animals, including humans, is enhanced by oral administration of the filtered product.
U.S. Pat. No. 4,816,252 to Stott et al. discloses a product and process for transferring passive immunity to newborn domestic animals using ultrafiltered whey containing immunoglobulins. Active immunoglobulins are extracted from the whey byproduct of dairy manufacturing, using ultrafiltration techniques to separate the large immuoglobulin molecules from the whey. The ultrafiltration retentate is dried to produce a filtered product having a high concentration of immunoglobulins. The dry filtered product is fed to newborn animals to transfer passive immunity. The whey-derived product is optionally used on a continuous basis as a food supplement for an animal to enable the immunologically active immunoglobulin molecules in the product to attack pathogens present in the digestive system of the animal.
U.S. Pat. No. 4,644,056 to Kothe el al. discloses a method of preparing a solution of lactic or colostric immunoglobulins or both, and use thereof, by processing milk or colostrum accompanied by precipitation of the caseins. The object of the invention is to provide a simple and economical method of preparing a solution of lactic or colostric immunoglobulins. A preferred starting material for the method in accordance with the invention is accordingly either colostrum from non-hyperimmunized mammals or human colostrum, with colostrum obtained from cows up to 30 hours after calving, with up to 5 hours after calving being particularly preferred.
Abe et al., J Dairy Sci. 78(12): 2838-46 (1995 Dec) disclose bifidobacteria and lactic acid bacteria. The bacteria are orally administered, resulting in an improvement in the general health of the calves receiving the bacteria. The article does not discuss or propose the use of a preparation of ruminal fluid in treatment of newborn calves.